Stationary Constant Velocity Universal Joint Cold-Forging Finishing
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Solution Overview
Problem
The existing methods for manufacturing fixed type constant velocity universal joints face challenges in reducing production costs and increasing productivity due to the need for additional processing steps and reduced accuracy in forming track grooves, while also encountering interference issues during cage incorporation, which affects the torque-bearing capacity and design flexibility.
Innovation Solution
The solution involves forming cage incorporating chamfers and track grooves using cold-forging finishing without turning, allowing for simultaneous high-accuracy formation of track grooves and chamfers, and incorporating cutout portions to prevent cage interference, thereby reducing production costs and time, and enhancing design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cold-forging finishing is used to form track grooves, then productivity increases and manufacturing cost decreases, but manufacturing precision of track grooves deteriorates
Solution Approach 1:
The invention combines the formation of track grooves and cage incorporating chamfers into a single cold-forging finishing operation. The groove forming punch simultaneously creates both the track grooves and the chamfers on the radially inner surface, eliminating the need for separate machining operations and achieving high productivity while maintaining sufficient precision for cage incorporation
Solution Approach 2:
The cage incorporating chamfers are formed in advance during the cold-forging finishing process, before the cage incorporation step. This preliminary formation of chamfers prevents interference during subsequent cage assembly, solving the precision issue by built-in design rather than post-processing
2Ease of manufacture
If the inlet diameter of the cup section is set larger than the outermost diameter of the cage hole portion, then the cage can be incorporated easily, but the constant velocity universal joint cannot be downsized
Solution Approach 1:
Instead of increasing the inlet diameter in the radial direction to facilitate cage incorporation, the invention creates chamfers in the axial direction on the radially inner surface. This dimensional approach allows the cage to be incorporated without increasing the overall radial size of the joint, enabling downsizing while maintaining ease of assembly
Solution Approach 2:
The cage incorporating chamfers are formed in advance during the cold-forging finishing process, before the cage incorporation step. This preliminary formation of chamfers prevents interference during subsequent cage assembly, solving the precision issue by built-in design rather than post-processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases productivity, reduces production costs, and ensures high accuracy and design flexibility by eliminating the need for additional processing steps and preventing cage interference, while maintaining excellent durability and torque-bearing capacity.
Implementation Method 1
the track grooves and the cage incorporating chamfers are finished by cold-forging ironing using a single ironing punch
Implementation Method 2
a columnar billet is formed by hot forging, warm forging, or cold forging into a schematic shape of the outer joint member
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An outer joint member includes a cutout portion that is formed at least at each corner portion on an opening side of a cup section, which is defined between a radially inner opening end portion of each of track grooves and a radially inner spherical surface portion formed between the track grooves. The cutout portion is configured to prevent a cage from interfering with the outer joint member when the cage is incorporated into the outer joint member. The cutout portion and the track grooves of the outer joint member are finished by cold-forging ironing using a single ironing punch.